PREIN

/bin/sh

getent group knot >/dev/null || groupadd -r knot
getent passwd knot >/dev/null || \
useradd -r -g knot -d /etc/knot -s /sbin/nologin \
-c "Knot DNS server" knot
exit 0

PREUN

/bin/sh

if [ $1 -eq 0 ] ; then 
        # Package removal, not upgrade 
        systemctl --no-reload disable knot.service > /dev/null 2>&1 || : 
        systemctl stop knot.service > /dev/null 2>&1 || : 
fi

POSTIN

/bin/sh

/sbin/ldconfig

if [ $1 -eq 1 ] ; then 
        # Initial installation 
        systemctl preset knot.service >/dev/null 2>&1 || : 
fi

POSTUN

/bin/sh

/sbin/ldconfig

systemctl daemon-reload >/dev/null 2>&1 || :